Mammatus

Clouds : classification

Genera

species

calvus cal
capillatus cap
castellanus cas
congestus con
fibratus fib
floccus flo
fractus fra
humilis hum
lenticularis len
mediocris med
nebulosus neb
spissatus spi
stratiformis st
uncinus unc
volutus vol

Subspecies

Special forms

arcus arc
asperitas asp
cauda cau
cavum cav
fluctus flu
flumen flm
incus inc
mamma mam
murus mur
pannus pan
pileus pil
praecipitatio pra
tuba tub
velum vel
virga vir

Mammatus (from Latin breast-like ; abbreviation: mam , short form mamma , plural Mammaten ) are bag-like formations hanging on the underside of clouds. The special form occurs most often on the anvil or umbrella of the cumulonimbus , but it can also be observed in cirrus , cirrocumulus , altocumulus , altostratus and stratocumulus as well as the ash clouds from erupting volcanoes . Mammates usually have smooth, laminar structures, but those on cirrus clouds in particular can also appear irregular. The vertical extent also varies depending on the cloud on which the mammates form. The main prerequisites for the formation of mammatus clouds are the current temperature and humidity gradients as well as the existing wind shear .

Mammates are generally little-researched weather phenomena. There are various theories about their origins, none of which have been proven. One of the best-known theories says that mammates are created by evaporation processes on the underside of the cloud, when the air layer under the cloud is cooled and labilized, which in turn creates buoyancy, which ultimately leads to the formation of the mammatus.

Mammats appear up to ten times more frequently in summer than in winter and can be recognized and observed with the help of Doppler radar systems.